As a head unit having suction nozzles for sucking and holding components in such a component mounting apparatus, for example, such a head unit 700 as shown in FIG. 3 has been known conventionally. In such a component mounting apparatus 1500 as shown in FIG. 24, for example, head unit 1700 is installed in an X-Y robot 1500X for moving the head unit 1700 in X-Y directions, suction nozzles of the head unit 1700 driven by the X-Y robot 1500X suck and hold components fed from component feeding units 1500H and 1500I for production of a mounted board 1500J and, after recognition of shapes of the components and correction of the postures thereof, the head unit mounts the components onto the board 1500J. Reference character 1500M in FIG. 24 denotes a motor that drives the head unit 1700 in the direction of Y axis of the X-Y robot 1500X and, during movement in the direction of Y axis, components sucked and held by the suction nozzles are moved over a recognition camera and recognized.
Such a head unit 770 as shown in FIG. 5 also has been known, and the head unit 770 has a configuration and a function which are similar to those of the head unit 700 of FIG. 3.
Hereinbelow, configurations of the head units 700 and 770 will be described.
In FIG. 3, reference numeral 701 denotes a frame that serves as a foundation of the head unit 700, and the frame moves about a component mounting apparatus in combination with a robot unit that drives the head unit 700 in X-Y directions of the component mounting apparatus. Reference numeral 702 denotes a motor that is a drive source and is integral with the frame, and thus a table 703 is moved in directions E and F, i.e., in vertical directions. Reference numerals 724 to 733 denote nozzles which suck and hold components, and the nozzles 724 to 733 are normally biased by springs 714 to 723 in a direction E so as to remain still. Reference numerals 704 to 713 denote cylinders which selectively transmit drives from the table 703 to the nozzles 724 to 733 in the directions E and F. From among the cylinders 704 to 713, only the cylinders corresponding to the nozzles to which actions are to be transmitted from the table 703 are driven to come into contact with only those nozzles (from among the nozzles 724 to 733) to effect forces in the direction E so that vertical movement of the table 703 causes movements of the selected nozzles in the directions E and F through actions of the driven cylinders. On the contrary, from among the cylinders 704 to 713, the cylinders which do not transmit movements in the directions E and F are not driven and do not come into contact with the nozzles 704 to 713 and therefore do not cause movements in the directions E and F.
Hereinbelow, movement of the head unit 700 configured as above will be described. In FIGS. 4A to 4C, only four nozzles 724, 725, 726, and 727 out of the ten nozzles are shown for brevity.
At commencement of recognition in FIG. 4A, for example, four nozzles 724, 725, 726, and 727 out of the ten nozzles simultaneously descend to a specified height while holding components 695, 696, 697, and 698, and the component 695, then the component 696, then the component 697 and then the component 698 are subsequently recognized in order of mention in accordance with a direction R of a movement of the head unit 700, via a recognition camera 600, i.e., a component shape recognition unit. At this time, focus of the recognition camera 600 is obtained in a diagonally shaded range P in FIG. 4A, and recognition can be achieved only in the range P. Bottom surfaces of the components 695, 696, and 697 can be positioned in the range P through vertical movements of the nozzles 724, 725, and 726, and can be recognized via the recognition camera 600. On the other hand, a bottom surface of the component 698 is out of the range P and cannot be recognized via the recognition camera 600. Accordingly, shapes of components having different heights such as the components 695, 696, and 697 and the component 698 cannot be recognized continuously, for example, in the order of the component 695, then the component 696, then the component 697 and then the component 698.
In practice, as shown in FIG. 4B, the shapes of the components 695, 696, and 697 which are held by the nozzles 724, 725, and 726 and can be simultaneously recognized are continuously recognized. After that, the component 698 is held by the nozzle 727 and then a height of the nozzle 727 relative to the recognition camera 600 is switched and the component 698 is recognized.
The configuration of the head unit 770 shown in FIG. 5 will be described below.
Reference numeral 771 denotes a frame that serves as a foundation of the head unit 770, and the frame 771 is integral with motors 772, 773, and 774 which are drive sources. Numerals 775, 776, and 777 denote ball screws which are rotated individually by the motors 772, 773, and 774, respectively, and numerals 778, 779, and 780 denote nozzles for holding components. Rotational drive caused by the motors 772, 773, and 774 is transmitted to the nozzles 778, 779, and 780 through a medium of the ball screws 775, 776, and 777 so as to move the nozzles vertically. As a result, settings of vertical movements of the nozzles 778, 779, and 780 can be individually provided by the motors 772, 773, and 774.
Hereinbelow, movement of the head unit 770 configured as above will be described.
In FIG. 6, drives of the nozzles 778, 779, and 780 in directions U and V, i.e., in upward and downward directions in FIG. 5 are individually controlled by the motors 772, 773, and 774. Thus, components 787, 788, and 789 are held respectively and then positions of the components are individually adjusted so that bottom surfaces of the components come into a recognizable range P in which focus of a component shape recognition unit 600 is obtained. In this manner, shape recognition and mounting of the components 787, 788, and 789 having different heights are performed continuously in the order of the component 787, then the component 788, and then the component 789.
On the other hand, such a configuration of the head unit 700 as mentioned above with reference to FIG. 3 causes an increase in the number of times of component shape recognition with an increase in a variety of heights of components to be mounted and, at the same time, causes an increase in a transit time of the head unit 700 for feeding of the components, so that an increase in tact time for mounting the components onto boards influences productivity of mounted boards.
In recent years, however, a need for mounting of various types of components has increased and component mounting apparatus which are capable of recognizing various components continuously have been essential for board mounting with high efficiency.
With such a configuration of the head unit 770 as mentioned above with reference to FIG. 5, shapes of components can be continuously recognized regardless of a difference in heights of the components; however, a necessity for a plurality of drive sources not only raises a cost of the head unit itself but may exert an influence on dynamic characteristics of a robot for driving the head unit because of an increase in weight of the head unit and other influences. This results in a limitation of the number of nozzles, which may inhibit improvement of efficiency of component mounting.
It is an object of the present invention to solve the above-mentioned issues; that is, to provide a component recognizing method and apparatus, and component mounting method and apparatus by which components with various heights held by a plurality of component holding members can be recognized continuously.